Steam turbine and turbine rotor

Abstract

High-temperature steam at 620° C. or higher is introduced to a reheat steam turbine 100 , and a turbine rotor 113 of the reheat steam turbine 100 includes: a high-temperature turbine rotor constituent part 113 a positioned in an area extending from a nozzle 114 a on a first stage to a moving blade 115 a on a stage where temperature of the steam becomes 550° C. and made of a corrosion and heat resistant material; and low-temperature turbine rotor constituent parts 113 b connected to and sandwiching the high-temperature turbine rotor constituent part 113 a and made of a material different from the material of the high-temperature turbine rotor constituent part 113 a.

1. A steam turbine having a turbine rotor to which high-temperature steam at 620° C. or higher is introduced, comprising:
 a high-temperature turbine rotor constituent part positioned in an area extending from a nozzle on a first stage to a moving blade on a stage where temperature of the steam becomes 550° C., the high-temperature turbine rotor constituent part being made of a corrosion and heat resistant material; 
 low-temperature turbine rotor constituent parts connected to and sandwiching the high-temperature turbine rotor constituent part, the low-temperature turbine rotor constituent part being made of a material different from the material of the high-temperature turbine rotor constituent part; 
 a joint portion positioned on an upstream side out of joint portions on an outer surface between the high-temperature turbine rotor constituent part and the low-temperature turbine rotor constituent part, the joint portion positioned on the upstream side being formed at a position corresponding to the nozzle on the first stage; 
 a joint portion positioned on a downstream side out of joint portions on an outer surface between the high-temperature turbine rotor constituent part and the low-temperature turbine rotor constituent part, the joint portion positioned on the downstream side being formed at a position on a downstream side of a nozzle positioned on an immediate downstream side of a moving blade on a stage where temperature of the steam becomes 550° C.; and 
 a cooling part configured to cool the joint portion on the downstream side out of the joint portions, the cooling part supplying a cooling steam to the upstream side of the nozzle positioned on the immediate downstream side of the moving blade on the stage where the steam temperature becomes 550° C. 
 
     
     
       2. The steam turbine according to  claim 1 ,
 wherein the corrosion and heat resistant material forming the high-temperature turbine rotor constituent part is a Ni-based alloy, and the material forming the low-temperature turbine rotor constituent parts is ferritic heat resistant steel. 
 
     
     
       3. The steam turbine according to  claim 1 ,
 wherein the high-temperature turbine rotor constituent part and the low-temperature turbine rotor constituent parts are connected by welding or bolting. 
 
     
     
       4. The steam turbine according to  claim 1 ,
 wherein, in a casing of the steam turbine connected to a nozzle diaphragm, a constituent portion covering the area in which the high-temperature turbine rotor constituent part is penetratingly provided is made of a corrosion and heat resistant material. 
 
     
     
       5. A turbine rotor penetratingly provided in a steam turbine to which high-temperature steam at 620° C. or higher is introduced, comprising:
 a high-temperature turbine rotor constituent part positioned in an area extending from a nozzle on a first stage in the steam turbine to a moving blade on a stage where temperature of the steam becomes 550° C., high-temperature turbine rotor constituent part being made of a corrosion and heat resistant material; and 
 low-temperature turbine rotor constituent parts connected to and sandwiching the high-temperature turbine rotor constituent part, the low-temperature turbine rotor constituent part being made of a material different from the material of the high-temperature turbine rotor constituent part; 
 a joint portion positioned on an upstream side out of joint portions on an outer surface between the high-temperature turbine rotor constituent part and the low-temperature turbine rotor constituent part, the joint portion positioned on the upstream side being formed at a position corresponding to the nozzle on the first stage in the steam turbine; and 
 a joint portion positioned on a downstream side out of joint portions on an outer surface between the high-temperature turbine rotor constituent part and the low-temperature turbine rotor constituent part, the joint portion positioned on the downstream side being formed at a position on a downstream side of a nozzle in the steam turbine positioned on an immediate downstream side of a moving blade on a stage where temperature of the stream becomes 550° C. 
 
     
     
       6. The turbine rotor according to  claim 5 ,
 wherein the corrosion and heat resistant material forming the high-temperature turbine rotor constituent part is a Ni-based alloy, and the material forming the low-temperature turbine rotor constituent parts is ferritic heat resistant steel. 
 
     
     
       7. The turbine rotor according to  claim 5 ,
 wherein the high-temperature turbine rotor constituent part and the low-temperature turbine rotor constituent parts are connected by welding or bolting.